1. Field of the Invention
The present invention relates generally to a flying magnetic head slider used in a magnetic disk drive, and more particularly to a negative-pressure slider intended for a low flying height.
2. Description of the Related Art
In a magnetic head slider for a recent magnetic disk drive, lowering the flying height is pursued to increase the recording density of a magnetic disk. Further, a slider having excellent flying stability is desired because a large acceleration is applied in an accessing direction to obtain a high access speed. Further, in a recent magnetic disk drive, a rotary positioner is widely used for the purposes of size reduction of the magnetic disk drive and simplification of a mechanism, and a negative-pressure slider with less variations in flying height due to changes in yaw angle is desired.
As a negative-pressure magnetic head slider having excellent flying stability, there has been proposed a slider having a pair of rails decreased in rail width from an air inlet end toward an air outlet end and defining a groove between the pair of rails to generate a negative pressure in the groove (Japanese Patent Laid-open No. 4-228157). FIG. 1A is a plan view of a conventional negative-pressure magnetic head slider disclosed in the above publication, and FIG. 1B is a perspective view of the slider shown in FIG. 1A. The slider denoted by reference numeral 2 has a rectangular shape as viewed in plan, and it has an air inlet end 2a and an air outlet end 2b.
A pair of rails 4 and 6 for generating a positive pressure are formed on a disk opposing surface of the slider 2. The rails 4 and 6 have flat air bearing surfaces (rails surfaces) 4a and 6a for generating a flying force during rotation of a disk, respectively. Tapering surfaces 4b and 6b are formed at the air inlet end portions of the rails 4 and 6, respectively. A groove 8 for expanding the air once compressed to generate a negative pressure is defined between the rails 4 and 6. An electromagnetic transducer 10 is formed on the air outlet end 2b of the slider 2 at a position where the rail 4 is located. A center rail 11 is formed between the rails 4 and 6 on the air inlet end 2a side.
Each of the rails 4 and 6 has a width larger at the air inlet end portion and the air outlet end portion and smaller at the intermediate portion, thereby suppressing variations in flying height due to changes in yaw angle. Further, by forming the tapering surfaces 4b and 6b at the air inlet end portions of the rails 4 and 6, variations in flying height due to deposition of dust can be suppressed. FIG. 1B is a perspective view of the slider 2 as viewed from the side of the rail surfaces, in which the broken arrows show a positive pressure acting on the slider 2, and the solid arrows show a negative pressure acting on the slider 2. The positive pressure is generated at the rail surfaces 4a and 6a, and the negative pressure is generated at the groove 8.
When the flying height of the slider 2 becomes 0.05 .mu.m or less, the shape of the slider largely affects a flying condition. The above-mentioned conventional slider is rectangular in shape and each of the pair of substantially parallel rails has two wider portions at the air inlet end portion and the air outlet end portion. Accordingly, four peaks are present in a pressure distribution in flying of the slider. That is, the slider is supported at four points in flying. In such a case that the slider is supported at four points in flying, the shape of the slider largely affects a flying condition. That is, the flying condition of the slider is largely varied with variations in crown, camber, twist, etc. of the slider due to a manufacturing error.